The roller mine was a type of droid manufactured on the world of Koboh. Once this droid identified a living being, it would emit a beam of light that would latch onto the target. Upon reaching a certain proximity, the beam's color would shift to red, signaling the impending explosion. The true history of the roller mine was largely unknown by 9 BBY. A common theory suggested that these droids were originally designed to clear stone and rubble, while others believed a priorite miner from long ago built them. The Gotarite miner named Soont Madas once tried deploying roller mines as a way to get into a Jedi Meditation Chamber located on Koboh. As part of this effort, he altered the programming of the mines, causing them to attack anyone in the area.